Stacker crane position control system with an auxillary verifying means

ABSTRACT

An automatic warehousing system comprising a storage structure defining a plurality of load-handling locations, and an automatic load carrier for delivering loads to and picking up loads from the load-handling locations, with the control system for the load carrier including command-receiving and movement-determining means for controlling the movement of the load carrier to a selected load-handling location, and with verifying means coacting with the control means for verifying the accuracy of the positioning of the load carrier at selected load-handling locations prior to final handling of loads by the load carrier at the selected storage locations.

United States Patent Inventor Sanlord Saul Cleveland, Ohio Appl. No.760,873

Filed Sept. 19,1968

Patented June l, 1971 Assignee The Triax Company Cleveland, Ohio STACKERCRANE POSITION CONTROL SYSTEM WITH AN AUXILLARY VERIFYING MEANS 12Claims, 23 Drawing Figs.

3,219,207 11/1965 Chasar .1 3,402,836 9/1968 Debreyetal....,.,...,

ABSTRACT: An automatic warehousing system comprising a storage structuredefining a plurality of load-handling locations, and an automatic loadcarrier for delivering loads to and picking up loads from theload-handling locations, with the control system for the load carrierincluding command-receiving and movement-determining means forcontrolling the movement of the load carrier to a selected load-handlinglocation, and with verifying means coacting with the control means forverifying the accuracy of the positioning of the load carrier atselected load-handling locations prior to final handling of loads by theload carrier at the selected storage locations.

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1. In an automatic warehousing system having a storage structure and aload-handling carrier for delivering and picking up loads at a pluralityof load storage locations in said storage structure, control means forsaid load carrier for controlling actuation of the latter to theselected load storage locations, and means coacting with said controlmeans for verifying the position of said load carrier as indicated bysaid control means for the selected load storage location, said controlmeans and said verifying means both including separate and independentsignal-Producing means for respectively signalling the position of saidload carrier in said storage structure, a common output means to whichsaid signal-producing means are operatively coupled, and meansresponsive to said output means to prevent actuation of said loadcarrier to handle a load at the then confronting storage location if theload carrier position as indicated by said control means fails to matchthe corresponding position as indicated by said verifying means.
 2. Asystem in accordance with claim 1 wherein said control means includesselector means and counting means comprising said signal-producing meansof said control means coacting with said selector means for controllingthe movement of said load carrier to the selected load storage location,and said verifying means includes duplicate counting means comprisingsaid signal-producing means of said verifying means in circuit with thefirst-mentioned counting means, and control elements in circuit withsaid counting means and said output means for permitting actuation ofsaid load carrier to pick up or deposit a load at a selected loadstorage location only when said counting means are in synchronism withone another.
 3. A system in accordance with claim 1 wherein said controlmeans includes selector means and counting means comprising saidsignal-producing means of said control means coacting with said selectormeans for controlling the movement of said load carrier to the selectedload storage location, and said verifying means includes sensor meanscomprising said signal-producing means of said verifying means operableto sense the position of said load carrier and in conjunction with saidoutput means and said responsive means operable to permit actuation ofsaid load carrier to pick up or deposit a load only in the event thatthe position of said load carrier as indicated by said sensor meanscorresponds to the position of said load carrier as indicated by saidselector means.
 4. A system in accordance with claim 3 wherein saidsensor means comprises mechanically responsive switch means actuatedinto conductive condition by movement of said load carrier to saidselected storage location to cause checking of said load carrierposition.
 5. A system in accordance with claim 3 wherein said sensormeans comprises light-responsive switch means actuated into conductivecondition by movement of said load carrier to said selected storagelocation to cause checking of said load carrier position.
 6. A system inaccordance with claim 3 wherein said sensor means comprises magneticallyresponsive switch means actuated into conductive condition by movementof said load carrier to said selected storage location to cause checkingof said load carrier position.
 7. A system in accordance with claim 1wherein said storage structure includes a pickup and discharge stationfrom which said load carrier commences its movement to deposit a loadinto or withdraw a load from a selected load storage location, andwherein said control means includes means operable to cause said loadcarrier to return to said pickup and discharge station in the event thatthe position of the load carrier as indicated by said verifying meansdoes not correspond to the position of the load carrier as indicated bysaid control means.
 8. A system in accordance with claim 1 wherein saidcontrol means includes selector means comprising switch means for eachof said storage locations in said storage structure, and being adaptedto be selectively actuated to define one or more load-handling storagelocations to which said load carrier is adapted to move during aload-handling cycle, and said signal-producing means of said verifyingmeans including means for checking the position of said load carrier asdesignated by said selector means for each of said storage locations. 9.A system in accordance with claim 1 wherein said control means includesselector means comprising switch means for each of said storagelocations in said storagE structure, and being adapted to be selectivelyactuated to define one or more load-handling storage locations to whichsaid load carrier is adapted to move during a load-handling cycle, andsaid signal-producing means of said verifying means including means forchecking the position of said load carrier as designated by only certainof said selector means for the storage locations, the last-mentionedchecking means being responsive to movement of said load carrier tocertain of said storage locations corresponding to said certain selectormeans for causing energization of said means preventing actuation ofsaid load carrier to deliver a load or pick up a load from the selectedstorage location in the event that the position of the load carrier asindicated by said verifying means does not correspond to the position ofsaid load carrier as indicated by said control means.
 10. A system inaccordance with claim 1 wherein said load carrier is movablehorizontally and vertically to a selected load storage location andlaterally into and out of the storage structure to deposit and to pickup loads, motor power means for actuating said load carrier, saidcontrol means being connected to said power means, said control meansincluding selector means for selecting to which of said load storagelocations said load carrier will move upon actuation thereof and saidverifying means verifying the accuracy of the positioning of the loadcarrier at a selected load storage location as indicated by saidselector means prior to said lateral movement of said load carrier tohandle a load at the selected storage location.
 11. A system inaccordance with claim 1 wherein said load carrier comprises a generallyhorizontally movable conveyor portion, an elevator portion movablegenerally vertically on said conveyor portion, and an extractor portionmounted on said elevator portion and adapted for lateral movement withrespect thereto to deposit and pickup loads at selected storagelocations in said storage structure, said verifying means includingmeans operative to verify both the horizontal and vertical positioningmovements of said load carrier in said storage structure.
 12. In anautomatic warehousing system having a storage structure and aload-handling carrier for delivering and picking up loads at a pluralityof load storage locations in said storage structure, control means forsaid load carrier for controlling the actuation of the latter to theselected load storage locations, and means coacting with said controlmeans for verifying the position of said load carrier as indicated bysaid control means for the selected storage location, said load carriercomprising a generally horizontally movable conveyor portion, anelevator portion movable generally vertically on said conveyor portionand an extractor portion mounted on said elevator portion adapted forlateral movement with respect thereto to deposit and pick up loads atselected storage locations in said storage structure, motor power meansfor actuating said load carrier, said control means being operablycoupled to said power means, said control means including selector meansfor selecting to which of said load storage locations said load carrierwill move upon actuation thereof, sensor means for sensing thehorizontal and vertical movements of said load carrier and means forreceiving commands and determining movements of said load carrier to theselected load storage locations via actuation of said power means, saidverifying means coacting with said command-receiving andmovement-determining means for verifying the accuracy of the positioningof the load carrier at a selected load storage location as indicated bysaid selector means prior to said lateral movement of said extractorportion of said load carrier to handle a load at the selected loadstorage location, and wherein said command-receiving andmovement-determining means includes first stepping switch means adaptedto be actuated in step fashion by said sensor meanS as said load carriermoves to a selected load storage location effective to actuate saidcontrol means and deenergize said motor power means to stop movement ofsaid load carrier at a selected load-handling storage location, and saidverifying means including other sensor means and second stepping switchmeans, said other sensor means being adapted to sense the horizontal andvertical movements of said load carrier independently of thefirst-mentioned sensor means and to actuate said second stepping switchmeans in step fashion as said load carrier moves to the selected storagelocation, and a common output means in circuit with said stepping switchmeans and responsive to the latter, and reject means responsive to saidoutput means to prevent actuation of said extractor portion to handle aload at the then confronting load storage location, if the load carrierposition as indicated by said control means fails to match the loadcarrier position indicated by said verifying means.